The Design Of Electrical Resistance Tomography Real-time Measurement System

With the continuous development of industrial technology, the demand for measuring the two-phase/multiphase flow is increasing, but high precision and real-time parameter measurement of multiphase flow has not been resolved effectively in engineering and scientific fields yet. By using the electrical resistance tomography (ERT) technology we can measure the internal parameters of the multiphase flow which has conductive medium as the continuous phase. At present, the main reason for affecting the industrial application of the ERT system is the contradiction of the real-time and nicety in detecting. To meet the needs of the actual industrial applications, we analyze real-time and high precision ERT measurement based on the basic principle of the ERT system.Firstly, we introduce the research background, research meaning, basic idea of this subject based on the contents and main results of the ERT research.Secondly, on the basis of analysising on ERT imaging principle, the various factors which influencing the accuracy and real-time, we introduce in detail the basic thoughts and the realize way of the real-time ERT measurement system from both hardware and software design. We use the excitation model of single electrode bi-directional pulse current to design the 16 electrodes ERT system. Under the control of microcontroller, using the DAC chip to generate the excitation source, the design can be simplified and the control module for synchronous data sampling can be not needed. Furthermore we use programmable amplifying circuit and high-precision data acquisition circuit to complete the signal processing and data acquisition, and use the serial mode to transmit the data in real-time. Based on the development environment of the Labwindows/CVI, we design the software processing platform which contains the function of serial communication, FEM mesh generation, the real-time data imaging and measurement.Finally, the performance test results and the further development trends are be offered. Based on the experiment of the sensor shape, the repeat precision of the data acquisition and the effect of real-time imaging, we test the real time and accuracy of the system. The test result indicates that by using the DAC chip to generate excitation signal, the ERT system can be simplied. On the basis of satisfying the real-time of signal excitation, data acquisition and software imaging, the designed system can reach the requirement of the subject in precision of imaging and measurement.